Rotary vibrator and mount therefor



Dec. 5, 1967 E. F. PETERSQN 3,355,957

ROTARY VIBRATOR AND MOUNT THEREFOR Filed Aug. 23, 1965 FIG. 2 ,e

FIG. 5

.M l INVENTOR.

F 6. 4 E. F. PETERSON United States Patent O 3,355,957 ROTARY VIBRATOR AND MOUNT THEREFOR Edwin F. Peterson, Neponset, Ill. 61345 Filed Aug. 23, 1965, Ser. No. 481,591 8 Claims. (Cl. 74-87) ABSTRACT F THE DISCLOSURE A rotary eccentricweight vibrator in which the casing is mounted by means including one or more screw type fasteners having a lead opposite to the direction of rotation of the weight.

This invention relates to a vibrator and more particularly to an improved mounting therefor in which the forces developed by rotation of an eccentric weight or mass are exploited to induce constant tightening of screwthreaded means employed in mounting the vibrator to an object to be vibrated.

A typical vibrator of the class with which the invention is especially concerned is shown in the U.S. patent to E. F. Peterson, 3,134,272, and comprises a carrier, usually a housing or casing, having imeans for iixed attachment thereof to an object to be vibrated, as in the cases of hopper cars, storage bins and other containers, conveyors, etc. for handling liuent materials such as coal, ore, gravel, grain, concrete and the like. The conventional vibrator has two pairs of legs arranged to straddle a web or flange rigid on the object to which the vibrator is attached and these legs have complementary screw-threaded means engageable with the web or flange to effect the necessary clamping action. The forces developed are of a relatively high order, as is known to those versed in the art, and

close attention must be devoted periodically to the mounting means to ascertain that it is secure. In some instances, resort has been had to the method of temporarily welding the vibrator in place, or of using special wedges and the like, but the former method is time-consuming and ultimately destructive and the latter suffers from the disadvantages that heavy releasing and attaching tools must be used and that parts may become lost, misplaced or broken. Consequently, the screw type mount has been most generally favored, since it lends itself best to mounting and dismounting of the vibrator, which must occur quite frequently as the vibrator is moved from one object to another or even among different locations on the same object.

According to the present invention, the discovery has been made that the direction of rotation of the vibrationinducing means, such as theeccentric weight, bears a definite relation to the direction of rotation of the screwthreaded lmounting members. Specifically where the axis of rotation of the screw means is parallel, or substantially so, to the axis of rotation of the weight means, tightening of the screw means will occur automatically when the direction of rotation of the weight means is opposite to the normal direction of tightening of the screw means. Speaking relatively, where the weight means rotates counterclockwise, the screw means has a right-hand thread and is turned clockwise for tightening action of the screw means. This principle can be carried into a mount having only one or one set of screw means localized at one side of a tiange or web or into a mount having sets of opposed generally coaxial screw means respectively at opposite sides of the iiange or web. In the latter case, the screw means must be of opposite hand Where they are simply clamping or set screws threaded respectively into tapped bores in the respective mounting legs.

As a matter of manufacturing and service economy, left hand threads are to be avoided where possible and there- 335'595'7 Patented Dec. 5, 1967 lCC fore the invention features application of the forcetightening principle to instances where a right-hand thread can be used and the weight means is turned left hand. In cases where the installation or mount requires use of the screw or screws at the opposite side, the principle is still applicable because the motor driving the rotary weight means is easily reversible from one side of the casing to the other.

Therefore, the objects of the invention are to provide an improved construction of the type referred to and to provide for the achievement of this and other objects in variant manners, all of which will become apparent as preferred embodiments of the invention are disclosed herein and with reference to the accompanying drawings wherein:

FIGURE 1 is a perspective of a typical vibrator and mount;

FIGURE 2 is an enlarged section generally on the line 2-2 of FIGURE 1;

FIGURE 3 is a schematic view of the axes and directions involved;

FIGURE 4 is a fragmentary section like the lower portion of FIGURE 2 but showing a different form of mount; and

FIGURE 5 is a schematic view like FIGURE 3 but showing the axes and directions involved in FIGURE 4.

The vibrator illustrated is like that in the above noted patent and has a rigid unitary or otherwise integrated carrier 10, here in the form of a steel casing or housing having opposite side walls 12, end walls 14, top 16 and a bottom 18. In the posture shown, the casing walls 12 are generally upright and parallel and the heavy rigid bottom wall is horizontal and elongated. The casing is also symmetrical as respects a median plane parallel to and intermediate the side walls 12. However, the casing or carrier may be otherwise configured and orientated, and the terminology employed here is therefore descriptive rather than limiting.

Bearings 20 in the side walls 12 journal a transverse tubular shaft 22 for rotation about an axis A (FIG. 3), which is here horizontal and normal to the above median plane. This shaft is coaxially keyed to and driven by a motor shaft 24 which is part of an externally mounted drive means, here an air motor 26, reversibility of the direction of rotation of which is easily achieved by interchanging the air line connections (not shown) between the inlet 28 and exhaust 30. The motor is typically secured to `one side wall 12 by a plurality of cap screws 32.

An eccentric mass or weight means 34 is disposed within the carrier 0r housing 10 intermediate the walls 12 and is fixed to the tubular shaft 22. 'In a symmetrical design as shown, the general plane of rotation 'of the weight means will coincide with the longitudinal median plane of the unit and of course will here be upright and therefore normal to the axis of rotation A. Because of the eccentricity of the weight, its rotation will set up vibratory forces of considerable magnitude, all as known to those versed in the art. i

The carrier or casing is rigidly equipped-here at its bottom-with means of mountingrthe vibrator on an object to be vibrated, the latter being typically provided with a webor ange-like support 36, here upright and centered on the above median plane. The mounting means comprises two pairs of legs or members rigidly united with the casing bottom and arranged in lengthwise spaced apart relation to straddle the web or flange 36. Each pair of legs includes inner and outer legs or'parts 38 and 40, the former of which is transversely bored and tapped at 42 to receive a tubular externally threaded bushing 44 that has a hardened inner end or nose 46. The bushing is also radially drilled at 48 to receive a lock pin 50 driven .in .exterorly `through `a .registering hole 52 in .the leg 3.8. The length of the pin is less than the inside diameter of the bushing so that it may be driven inwardly by a punch, .for example, in `order '.to enable the bushing 3S to be removed for resharpening, replacement etc. The .threading -t Y42l is conventionally vright-handed so that left-.hand :threads yare avoided in the interests of manufacturing 4and service economy.

The .other .leg 4.0 .is `similarly bored and tapped at 54, coaxially, or substantially so, with Vthe bore and tap at 47. in the leg 30, and a bushing v56 having external rightharid threads yis threaded .tig'htly'into the leg. The threads 4at 42 and 54 are preferably the .same so that the bushings 44 and 56 ymay be interchanged, as will be made `clear below. The leg 4i) .has a hole 58 like the hole 52 in the fleg 38.

The bushing 56 differs, however, from .the bushing 44 in that it is internally threaded (right-hand) at 60 to receive y,a .right-hand-threaded set or clamp screw 62, the inner end of which is a hardened nose 64 for engagement with the support web .36 in opposition .to the hard nose 46 of the bushing 44. If desired, a pin (not shown) may be used .in the 4hole 58 to pin the bushing 56.

The other pair of legs (FIG. 3) are identically constructed Vand providedrespectively with a bushing 44 and set .screw 62. In ythis ligure the axis of rotation A of the weight means will be seen to be parallel to the axes of rotation .B of the screws 62. Since the screws have `righthand threads, the direction of rotation of .each for tightening enga-gement with the -support .36 is clockwise, designated by arrows C, whereas the direction of rotation of Vthe weight lmeans 34 is counterclockwise (arrow D). These fdirections are of course as seen by an observer from .one side of .the device, here to the right side of the page Aor from the .same side as FIG. 1 is viewed. If the Ythreads .of .screws 62 were left hand, then the motor direction would be reversed. In other words, the direction of rotation of the weight means 34 is opposite to that of normal .tightening of t'he screws 62, with the result that operation .of the vibrator creates forces that induce constant and automatic tightening of these screws.

Experience has .shown that the tightening phenomenon increases as the rforce and frequency of the vibration increases. It is believed that this is due to the fact that a .certain level of force causes slippage between the inclined plane faces of the thread forms on the screw and in the :tapped bore. This does not refer to the inclined plane of .the lead `of the thread but refers rather to the inclined angle (usually 60) of the thread form itself, and this lies 'crosswise to the axis of 4t-he screw. The rotating force vector of the weight means is imposed upon the screw, :cau-sing the latter to tend -to rotate lin the direction opposite to that of the direction of rotation of the force vector.

I-n .some installations, design and construction characteriistics `may involve mounting the vibrator in such position that there Yis room for the motor V26 at the side .shown but no :room for the set screws 62, whereas there will be room for vthese `'screws .at the opposite side. In such case., the bushings 44 and 56 are interchanged between the legs .38 fand 40, the bushings 44 are pinned to the legs 40, the bushings 56 screwed into the legs 38 and the set screws threaded into the bushings 56. Now, looking at FIGS. l and 3 from :the same side as before, tightening rotation of the 'screws -62 will be "counterclockwise or in the same direction as rotation ofthe weight. Therefore, the direction of .rotation of 'the motor must 'be reversed so that it becomes 'opposite to screw rotation. The same automatic tightening will 'then 'be achieved.

FIGS. 4 and 5 illustrate use of the principle where the vibrator is equipped with two pairs of legs 38 and 40,

bushings 44' and '56 and set screws 62 and 63', except in this ease the bushings 44' and screws 63 have left-hand 'threads and the bushings 56 and screws 62 have righthand threads (viewed in the posture of FIG. 5 where the `direction of rotation of the motor 2.6 is counterclock- Wise as :before: arrow D). The tightening rotation of screws 62 will be as before: clockwise (arrows C) and the tightening directions of screws 63' will also be clockwise (arrows C") as seen from the same vantage point. Thus, both sets :of screws will benefit from ,the Vopposite rotation (arrow D) of vthe weight means about axis A. Each set of screw means 62'-63, 62263" rotates of course about its respective common axis B (substantially parallel to axis A).

Features and advantages -other ythan 4those enumerated will readily occur to those versed in the art, as will modications suggested by the disclosure here, all without departure from the spirit and scope of the invention.

What is claimed is:

1. A vibrator of the class described, ycomprising a rigid carrier, weight means .journaled :by .the carrier for rotation about an axis of rotation to which the mass of the weight means is eccentric, means for Vmounting the 4carrier on a flange-like support disposed normal to said axis of rotation, said mounting means yincluding a part lrigid wit-h the carrier Vfor positioning alongside said 'angellike support and a member engageable with `said `support and rotatably connected to said part by screw 'threads formed about an axis substantially lparallel to the axis of rotation of the weight means, the lead lof the screw being ysuch that rotation of the member about the axis of the screw threads in one direction causes tightening vof Vthe engagement of said member with the support, and means *for rotating the weight means about its axis of rotation in the direction opposite to tightening rotation of said member.

2. '1i-he invention defined in claim -1, including second mounting similar to the first-mentioned mounting means and spaced therefrom lengthwise of said support and including la part, a member and screw threads constructed like those of said first-mentioned mounting means.

3. A vibrator of the class described, comprising a rigid c arrier, weight means journaled -by the carrier for rotation about an axis of rotation to which the mass of the weight means is eccentric, means for mounting tbe -car rier on a flange-like support disposed -normal to said ax-is of rot-ation, said mounting means including a part rigid with the carrier for positioning alongside said lian-gelike -support and a member engageable with said support and rotatably connected lto said part iby screw threads formed about an axis substantially parallel to the axis Soif rotation of the weight means, and means for rotating the weight means about its axis of rotation in Vsuch direction that the vibratory .forces created thereby .induce tighten ing of 'the engagement of the member with said support.

4.. A vibrator vof the class described, 'comprising .a .rigid carrier, weight means journaled ,by the carrier for -rotation about an axis of rotation to which the mass of l-the weight means is eccentric, means for mounting the carrier on a flange-like support disposed normal to said axis of rotation, said mounting means including .a pair -of opposed parts rigid with the carrier .and .adapted to 'stradd'le said Asupport and means for clamping the .parts yto the sup port, including a member engageable with said .support and rotatably connected to at lea-st one .of said .parts by screw threads formed about an axis substantially parallel to the axis of rotation of the weight means, the lead 'of the screw being such that rotation V.of the member about the axis of the screw threads in one direction causes tightening of the clamping effect of said mounting means on the support, .and means for rotating the weight means about its axis of rotation in the direction opposite to tightening rotation of said member.

5. The invention defined in claim 4, including ysecond mounting similar to the yfirst-mentioned mounting means and .spaced therefrom lengthwise of said support vand :including a second pair of parts adapted to stra-delle the support and a second member screw-threadedly coni nected to at least one part of the second pair of parts and having a tightening rotation opposite to the direction of rotation of the weight means.

6. A vibrator of the class described, comprising a rigid carrier, Weight means journaled by the carrier for rotation about lan axis of rotation to which the mass of the weight means is eccentric, means for mounting the carrier on a flange-like support disposed normal to said axis of rotation, said mounting means including a pair of parts rigid with the carrier and spaced apart lengthwise of and adapted to lie alongside said support and a pair of members, one for each part, engageable with said support, each member being rotatably connected to its part by screw threads formed about an axis substantially parallel to the axis of rotation of the weight means, and means for rotating the weight means about its axis of rotation in such direction that the vibratory forces created thereby induce tightening of the engagement of the members with said support.

7. The invention defined in claim 3, in which: the mounting means includes a second part rigid with the carrier and adapted to lie along the opposite side of the support in oppositori to the first-named part, and a second member engageable with the sup-port at said opposite side thereof and rotatably connected to the second part by screw threads of such lead as to cause tightening engagement of said second member with the support by said rotation of the weight means.

8. The invention defined in claim 7, in which: a second mounting means is rigid on the carrier in spaced relation to the first-named mounting means and spaced therefrom lengthwise of the support, said second mounting means including third and fourth parts disposed in opposed relation to each other at opposite sides of the support and third and fourth members engageable with the support from opposite sides and rotatably connected respectively to said third and fourth parts by screw threads of such lead as to cause tightening engagement of said second member with the support by said rotation of the weight means.

References Cited UNITED STATES PATENTS 1,831,813 11/1931 Levedahl 77-55 3,076,346 2/ 1963 Peterson 74--606 3,134,272 5/1964 Peterson a 74-606 MARTIN P. SCHWADRON, Primary Examiner.

CORNELIUS I. HUSAR, Examiner. 

1. A VIBRATOR OF THE CLASS DESCRIBED, COMPRISING A RIGID CARRIER, WEIGHT MEANS JOURNALED BY THE CARRIER FOR ROTATION ABOUT AN AXIS OF ROTATION TO WHICH THE MASS OF THE WEIGHT MEANS IS ECCENTRIC, MEANS FOR MOUNTING THE CARRIER ON A FLANGE-LIKE SUPPORT DISPOSED NORMAL TO SAID AXIS OF ROTATION, SAID MOUNTING MEANS INCLUDING A PART RIGID WITH THE CARRIER FOR POSITIONING ALONGSIDE SAID FLANGE-LIKE SUPPORT AND A MEMBER ENGAGEABLE WITH SAID SUPPORT AND ROTATABLY CONNECTED TO SAID PART BY SCREW THREADS FORMED ABOUT AN AXIS SUBSTANTIALLY PARALLEL TO THE AXIS OF ROTATION OF THE WEIGHT MEANS, THE LEAD OF THE SCREW BEING SUCH THAT ROTATION OF THE MEMBER ABOUT THE AXIS OF THE SCREW THREADS IN ONE DIRECTION CAUSES TIGHTENING OF THE ENGAGEMENT OF SAID MEMBER WITH THE SUPPORT, AND MEANS FOR ROTATING THE WEIGHT MEANS ABOUT ITS AXIS OF ROTATION IN THE DIRECTION OPPOSITE TO TIGHTENING ROTATION OF SAID MEMBER. 